Inhibition of leukotriene biosynthesis has been an active area of pharmaceutical research for many years. Leukotrienes are potent contractile and inflammatory mediators derived through the oxygenation of arachidonic acid by 5-lipoxygenase.
One class of leukotriene biosynthesis inhibitors are those known to act through inhibition of 5-lipoxygenase (5-LO). In general, 5-LO inhibitors have been sought for the treatment of allergic rhinitis, asthma and inflammatory conditions including arthritis. One example of a 5-LO inhibitor is the marketed drug zileuton, which is indicated for the treatment of asthma. More recently, it has been reported that 5-LO may be an important contributor to the atherogenic process; see Mehrabian, M. et al., Circulation Research, 2002 Jul. 26, 91(2):120-126.
A new class of leukotriene biosynthesis inhibitors (now known as FLAP inhibitors) distinct from 5-LO inhibitors is described in Miller, D. K. et al., “Identification and isolation of a membrane protein necessary for leukotriene production,” Nature, vol. 343, No. 6255, pp. 278-281 (18 Jan. 1990). See also Dixon, R. A. et al, “Requirement of a 5-lipoxygenase-activating protein for leukotriene synthesis,” Nature, vol 343, no. 6255, pp. 282-4 (18 Jan. 1990). 5-LO inhibitor compounds were used to identify and isolate the inner nuclear membrane 18,000 dalton protein 5-lipoxygenase-activating protein (FLAP). These compounds inhibit the formation of cellular leukotrienes but have no direct effect on soluble 5-LO activity. In cells, arachidonic acid is released from membrane phospholipids by the action of cytosolic phospholipase 2. This arachidonic acid is transferred to nuclear membrane bound 5-lipoxygenase by FLAP. The presence of FLAP in cells is essential for the synthesis of leukotrienes. Additionally, based on studies described in Helgadottir, A., et al., Nature Genetics, vol 36, no. 3 (March 2004) pp. 233-239, it is believed that the gene encoding 5-lipoxygenase activating protein confers risk for myocardial infarction and stroke in humans.
Despite significant therapeutic advances in the treatment and prevention of atherosclerosis and ensuing atherosclerotic disease events, such as the improvements that have been achieved with HMG-CoA reductase inhibitors, further treatment options are clearly needed. The instant invention addresses that need by providing compounds, compositions and methods for the treatment or prevention of atherosclerosis as well as related conditions.